Large-scale energy storage systems can be created by coupling a number of energy storing devices such as batteries to one another. Such systems are useful for storing power during off-peak times and supplying electric power to an electric power transmission system during times of peak usage. This process is known as "peak shaving." A system that can be used to accomplish peak shaving is shown in U.S. Pat. No. 5,610,802 (the "'802 Patent").
Systems such as the one in the '802 Patent are most often implemented with metal-halogen batteries such as zinc bromine batteries. While zinc-bromine batteries have several advantages over other types of batteries, most such batteries suffer from bromine leakage problems. Bromine leakage causes power losses and corrosion and handling problems. Handling problems can be particularly troublesome since bromine is hazardous to both plants and animals.
Often times bromine leaks occur through battery vents which are provided to allow the internal pressure to equalize with the ambient pressure outside the battery, and for the escape of gases that build up inside the battery. However, vents equipped with scrubbers can reduce the effects of such leaks. More troublesome are leaks which occur in the battery components due to improper sealing or joining. These leaks are often compounded when batteries or modules containing batteries are transported, as the motion and vibration associated with such movement tends to further separate imperfect joints and seals in a battery.
In response to these problems, methods of strongly sealing the electrodes and separators used to create the electrochemical cells in zinc-bromine batteries have been developed. However, other components such a pump mounts, plumbing, and reservoirs may be imperfectly sealed, joined, or constructed and leak bromine, whether in a liquid or gaseous form. To date, most attempts to address such leaks have focused on providing sumps and other basins to catch and collect liquid bromine. However, these attempts have not been completely effective. Thus, there is a need for improved designs that reduce and prevent spills and leaks of bromine from zinc-bromine batteries.